With the recognition that cancer is a genetic disease, many cancer researchers, including scientists in the Mayo Clinic Cancer Center (MCCC), require access to routine and advanced cytogenetics services. These services include routine cytogenetic analysis, spectral karyotype (SKY) analyses of metaphases, interphase and metaphase fluorescence in situ hybridization (FISH), comparative genomic hybridization (CGH), and schedulable fluorescent microscope and imaging system time. Such services can aid in the identification of genetic regions important for the development of specific malignancies. Such services can also be used to characterize the clonality of tumor specimens and determine the origin (e.g., mouse vs. human) of a specific tumor culture. The shared resource has supported the research of over 30 Cancer Center members during the past 5-year funding period, performing routine cytogenetic, CGH, SKY and FISH analyses on over 100,70, 30 and 900 cases, respectively. The shared resource plans to add comparative genomic hybridization to array (CGHa) services. Thus, the Cytogenetics Shared Resource provides routine cytogenetic and advanced molecular cytogenetic services to MCCC members.